package com.qms.repast.net;

import com.orhanobut.logger.Logger;

import java.io.IOException;
import java.io.InputStream;
import java.security.KeyManagementException;
import java.security.KeyStore;
import java.security.NoSuchAlgorithmException;
import java.security.cert.Certificate;
import java.security.cert.CertificateException;
import java.security.cert.CertificateFactory;
import java.security.cert.X509Certificate;

import javax.net.ssl.HostnameVerifier;
import javax.net.ssl.KeyManager;
import javax.net.ssl.KeyManagerFactory;
import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSession;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.TrustManager;
import javax.net.ssl.TrustManagerFactory;
import javax.net.ssl.X509TrustManager;

/**
 * @author 泅渡者
 * @date 2018/8/31 0031
 * @describe:
 */
public class HttpsUtils {

	public static class SslParams {
		public SSLSocketFactory sSLSocketFactory;
		public X509TrustManager trustManager;
	}

	public static SslParams getSslSocketFactory () {
		return getSslSocketFactoryBase(null, null, null);
	}

	/**
	 * https单向认证 可以额外配置信任服务端的证书策略，否则默认是按CA证书去验证的，若不是CA可信任的证书，则无法通过验证
	 */
	public static SslParams getSslSocketFactory (X509TrustManager trustManager) {
		return getSslSocketFactoryBase(trustManager, null, null);
	}

	/**
	 * https单向认证 用含有服务端公钥的证书校验服务端证书
	 */
	public static SslParams getSslSocketFactory (InputStream... certificates) {
		return getSslSocketFactoryBase(null, null, null, certificates);
	}

	/**
	 * https双向认证 bksFile 和 password -> 客户端使用bks证书校验服务端证书 certificates -> 用含有服务端公钥的证书校验服务端证书
	 */
	public static SslParams getSslSocketFactory (InputStream bksFile, String password, InputStream... certificates) {
		return getSslSocketFactoryBase(null, bksFile, password, certificates);
	}

	/**
	 * https双向认证 bksFile 和 password -> 客户端使用bks证书校验服务端证书 X509TrustManager ->
	 * 如果需要自己校验，那么可以自己实现相关校验，如果不需要自己校验，那么传null即可
	 */
	public static SslParams getSslSocketFactory (InputStream bksFile, String password, X509TrustManager trustManager) {
		return getSslSocketFactoryBase(trustManager, bksFile, password);
	}

	private static SslParams getSslSocketFactoryBase (X509TrustManager trustManager, InputStream bksFile, String password, InputStream... certificates) {
		SslParams sslParams = new SslParams();
		try {
			KeyManager[] keyManagers = prepareKeyManager(bksFile, password);
			TrustManager[] trustManagers = prepareTrustManager(certificates);
			X509TrustManager manager;
			if (trustManager != null) {
				//优先使用用户自定义的TrustManager
				manager = trustManager;
			} else if (trustManagers != null) {
				//然后使用默认的TrustManager
				manager = chooseTrustManager(trustManagers);
			} else {
				//否则使用不安全的TrustManager
				manager = UnSafeTrustManager;
			}
			// 创建TLS类型的SSLContext对象， that uses our TrustManager
			SSLContext sslContext = SSLContext.getInstance("TLS");
			// 用上面得到的trustManagers初始化SSLContext，这样sslContext就会信任keyStore中的证书
			// 第一个参数是授权的密钥管理器，用来授权验证，比如授权自签名的证书验证。第二个是被授权的证书管理器，用来验证服务器端的证书
			sslContext.init(keyManagers, new TrustManager[]{manager}, null);
			// 通过sslContext获取SSLSocketFactory对象
			sslParams.sSLSocketFactory = sslContext.getSocketFactory();
			sslParams.trustManager = manager;
			return sslParams;
		} catch (NoSuchAlgorithmException e) {
			throw new AssertionError(e);
		} catch (KeyManagementException e) {
			throw new AssertionError(e);
		}
	}

	private static KeyManager[] prepareKeyManager (InputStream bksFile, String password) {
		try {
			if (bksFile == null || password == null) {
				return null;
			}
			KeyStore clientKeyStore = KeyStore.getInstance("BKS");
			clientKeyStore.load(bksFile, password.toCharArray());
			KeyManagerFactory kmf = KeyManagerFactory.getInstance(KeyManagerFactory.getDefaultAlgorithm());
			kmf.init(clientKeyStore, password.toCharArray());
			return kmf.getKeyManagers();
		} catch (Exception e) {
			Logger.e(e.getMessage());
		}
		return null;
	}

	private static TrustManager[] prepareTrustManager (InputStream... certificates) {
		if (certificates == null || certificates.length <= 0) {
			return null;
		}
		try {
			CertificateFactory certificateFactory = CertificateFactory.getInstance("X.509");
			// 创建一个默认类型的KeyStore，存储我们信任的证书
			KeyStore keyStore = KeyStore.getInstance(KeyStore.getDefaultType());
			keyStore.load(null);
			int index = 0;
			for (InputStream certStream : certificates) {
				String certificateAlias = Integer.toString(index++);
				// 证书工厂根据证书文件的流生成证书 cert
				Certificate cert = certificateFactory.generateCertificate(certStream);
				// 将 cert 作为可信证书放入到keyStore中
				keyStore.setCertificateEntry(certificateAlias, cert);
				try {
					if (certStream != null) {
						certStream.close();
					}
				} catch (IOException e) {
					Logger.e(e.getMessage());
				}
			}
			//我们创建一个默认类型的TrustManagerFactory
			TrustManagerFactory tmf = TrustManagerFactory.getInstance(TrustManagerFactory.getDefaultAlgorithm());
			//用我们之前的keyStore实例初始化TrustManagerFactory，这样tmf就会信任keyStore中的证书
			tmf.init(keyStore);
			//通过tmf获取TrustManager数组，TrustManager也会信任keyStore中的证书
			return tmf.getTrustManagers();
		} catch (Exception e) {
			Logger.e(e.getMessage());
		}
		return null;
	}

	private static X509TrustManager chooseTrustManager (TrustManager[] trustManagers) {
		for (TrustManager trustManager : trustManagers) {
			if (trustManager instanceof X509TrustManager) {
				return (X509TrustManager) trustManager;
			}
		}
		return null;
	}

	/**
	 * 为了解决客户端不信任服务器数字证书的问题，网络上大部分的解决方案都是让客户端不对证书做任何检查， 这是一种有很大安全漏洞的办法
	 */
	public static X509TrustManager UnSafeTrustManager = new X509TrustManager() {
		@Override
		public void checkClientTrusted (X509Certificate[] chain, String authType) throws CertificateException {
		}

		@Override
		public void checkServerTrusted (X509Certificate[] chain, String authType) throws CertificateException {
		}

		@Override
		public X509Certificate[] getAcceptedIssuers () {
			return new java.security.cert.X509Certificate[]{};
		}
	};

	/**
	 * 此类是用于主机名验证的基接口。 在握手期间，如果 URL 的主机名和服务器的标识主机名不匹配， 则验证机制可以回调此接口的实现程序来确定是否应该允许此连接。策略可以是基于证书的或依赖于其他验证方案。
	 * 当验证 URL 主机名使用的默认规则失败时使用这些回调。如果主机名是可接受的，则返回 true
	 */
	public static HostnameVerifier UnSafeHostnameVerifier = new HostnameVerifier() {
		@Override
		public boolean verify (String hostname, SSLSession session) {
			return true;
		}
	};
}